/*
 * Created on 4 Oct 2006
 * Created by Paul Gardner
 * Copyright (C) Azureus Software, Inc, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

package com.aelitis.azureus.core.networkmanager.impl.http;

import java.io.IOException;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.StringTokenizer;

import org.gudy.azureus2.core3.disk.DiskManager;
import org.gudy.azureus2.core3.disk.DiskManagerFileInfo;
import org.gudy.azureus2.core3.internat.MessageText;
import org.gudy.azureus2.core3.peer.impl.PEPeerControl;
import org.gudy.azureus2.core3.peer.impl.PEPeerTransport;
import org.gudy.azureus2.core3.torrent.TOTorrent;
import org.gudy.azureus2.core3.torrent.TOTorrentFile;
import org.gudy.azureus2.core3.util.Debug;

import com.aelitis.azureus.core.networkmanager.NetworkConnection;
import com.aelitis.azureus.core.util.HTTPUtils;

public class HTTPNetworkConnectionFile extends HTTPNetworkConnection {
    private boolean switching;

    protected HTTPNetworkConnectionFile(HTTPNetworkManager _manager, NetworkConnection _connection, PEPeerTransport _peer) {
        super(_manager, _connection, _peer);
    }

    protected void decodeHeader(HTTPMessageDecoder decoder, final String header)

    throws IOException {
        if (switching) {

            Debug.out("new header received while paused");

            throw (new IOException("Bork"));
        }

        if (!isSeed()) {

            return;
        }

        PEPeerControl control = getPeerControl();

        DiskManager dm = control.getDiskManager();

        if (dm == null) {

            Debug.out("Disk manager is null");

            throw (new IOException("Disk manager unavailable"));
        }

        TOTorrent to_torrent = dm.getTorrent();

        char[] chars = header.toCharArray();

        int last_pos = 0;
        int line_num = 0;

        String target_str = null;

        DiskManagerFileInfo target_file = null;

        long file_offset = 0;

        List<long[]> ranges = new ArrayList<long[]>();

        boolean keep_alive = false;

        for (int i = 1; i < chars.length; i++) {

            if (chars[i - 1] == '\r' && chars[i] == '\n') {

                String line = new String(chars, last_pos, i - last_pos).trim();

                last_pos = i;

                line_num++;

                // System.out.println( "line " + line_num + " -> " + line );

                if (line_num == 1) {

                    line = line.substring(line.indexOf("files/") + 6);

                    int hash_end = line.indexOf("/");

                    final byte[] old_hash = control.getHash();

                    final byte[] new_hash = URLDecoder.decode(line.substring(0, hash_end), "ISO-8859-1").getBytes("ISO-8859-1");

                    if (!Arrays.equals(new_hash, old_hash)) {

                        switching = true;

                        decoder.pauseInternally();

                        flushRequests(new flushListener() {
                            private boolean triggered;

                            public void flushed() {
                                synchronized (this) {

                                    if (triggered) {

                                        return;
                                    }

                                    triggered = true;
                                }

                                getManager().reRoute(HTTPNetworkConnectionFile.this, old_hash, new_hash, header);
                            }
                        });

                        return;
                    }

                    line = line.substring(hash_end + 1);

                    line = line.substring(0, line.lastIndexOf(' '));

                    String file = line;

                    if (to_torrent.isSimpleTorrent()) {

                        // optimise for simple torrents. also support the case where
                        // client has the hash but doesn't know the file name

                        target_file = dm.getFiles()[0];

                    } else {

                        target_str = file;

                        StringTokenizer tok = new StringTokenizer(file, "/");

                        List<byte[]> bits = new ArrayList<byte[]>();

                        while (tok.hasMoreTokens()) {

                            bits.add(URLDecoder.decode(tok.nextToken(), "ISO-8859-1").getBytes("ISO-8859-1"));
                        }

                        // latest spec has torrent file name encoded first for non-simple torrents
                        // remove it if we find it so we have some backward compat

                        if (!to_torrent.isSimpleTorrent() && bits.size() > 1) {

                            if (Arrays.equals(to_torrent.getName(), (byte[]) bits.get(0))) {

                                bits.remove(0);
                            }
                        }

                        DiskManagerFileInfo[] files = dm.getFiles();

                        file_offset = 0;

                        for (int j = 0; j < files.length; j++) {

                            TOTorrentFile torrent_file = files[j].getTorrentFile();

                            byte[][] comps = torrent_file.getPathComponents();

                            if (comps.length == bits.size()) {

                                boolean match = true;

                                for (int k = 0; k < comps.length; k++) {

                                    if (!Arrays.equals(comps[k], (byte[]) bits.get(k))) {

                                        match = false;

                                        break;
                                    }
                                }

                                if (match) {

                                    target_file = files[j];

                                    break;
                                }
                            }

                            file_offset += torrent_file.getLength();
                        }
                    }
                } else {

                    line = line.toLowerCase(MessageText.LOCALE_ENGLISH);

                    if (line.startsWith("range") && target_file != null) {

                        line = line.substring(5).trim();

                        if (line.startsWith(":")) {

                            String range_str = line.substring(1).trim();

                            if (range_str.startsWith("bytes=")) {

                                long file_length = target_file.getLength();

                                StringTokenizer tok2 = new StringTokenizer(range_str.substring(6), ",");

                                while (tok2.hasMoreTokens()) {

                                    String range = tok2.nextToken();

                                    try {
                                        int pos = range.indexOf('-');

                                        if (pos != -1) {

                                            String lhs = range.substring(0, pos);
                                            String rhs = range.substring(pos + 1);

                                            long start;
                                            long end;

                                            if (lhs.length() == 0) {

                                                // -222 is last 222 bytes of file

                                                end = file_length - 1;
                                                start = file_length - Long.parseLong(rhs);

                                            } else if (rhs.length() == 0) {

                                                end = file_length - 1;
                                                start = Long.parseLong(lhs);

                                            } else {

                                                start = Long.parseLong(lhs);
                                                end = Long.parseLong(rhs);
                                            }

                                            ranges.add(new long[] { start, end });
                                        }
                                    } catch (Throwable e) {
                                    }
                                }
                            }

                            if (ranges.size() == 0) {

                                log("Invalid range specification: '" + line + "'");

                                sendAndClose(getManager().getRangeNotSatisfiable());

                                return;
                            }
                        }
                    } else if (line.indexOf("keep-alive") != -1) {

                        keep_alive = true;
                    }
                }
            }
        }

        if (target_file == null) {

            log("Failed to find file '" + target_str + "'");

            sendAndClose(getManager().getNotFound());

            return;
        }

        try {
            String name = target_file.getFile(true).getName();

            int pos = name.lastIndexOf(".");

            if (pos != -1) {

                setContentType(HTTPUtils.guessContentTypeFromFileType(name.substring(pos + 1)));
            }
        } catch (Throwable e) {
        }

        long file_length = target_file.getLength();

        boolean partial_content = ranges.size() > 0;

        if (!partial_content) {

            ranges.add(new long[] { 0, file_length - 1 });
        }

        long[] offsets = new long[ranges.size()];
        long[] lengths = new long[ranges.size()];

        for (int i = 0; i < ranges.size(); i++) {

            long[] range = (long[]) ranges.get(i);

            long start = range[0];
            long end = range[1];

            if (start < 0 || start >= file_length || end < 0 || end >= file_length || start > end) {

                log("Invalid range specification: '" + start + "-" + end + "'");

                sendAndClose(getManager().getRangeNotSatisfiable());

                return;
            }

            offsets[i] = file_offset + start;
            lengths[i] = (end - start) + 1;
        }

        addRequest(new httpRequest(offsets, lengths, file_length, partial_content, keep_alive));
    }
}
